System and method predicting and managing network capacity requirements

ABSTRACT

A system and method for maintaining capacity of a network. Instructions are adapted to define future times at which a capacity of the network is evaluated. In addition, instructions are adapted to determine a total capacity of the network (TNC) and a total demand of users (TUD) for the network at each of the future times. As a function of the total capacity of the network (TNC) and the total demand of users (TUD), instructions are adapted to determine a predicted utilization (PU) of the network at each of the future times. By comparing the predicted utilization (PU) to a defined acceptable utilization of the network at each of the future times, instructions are adapted to determine a change in network capacity (DCNC) to be applied to the network at each of the future times in order to increase or decrease the capacity of the network.

FIELD OF THE INVENTION

Embodiments of the invention generally relate to network capacityforecasting and management as well as user demand forecasting. Inparticular, embodiments of the invention relate to a system and methodfor evaluating and for taking into account various factors in order topredict and maintain a capacity of a communications network to meetanticipated needs and changes at some future point in time.

BACKGROUND OF THE INVENTION

In the past, managers of networks such as communications networks faceda severe challenge in trying to predict impacts of ever changing networkcapacity requirements. Particularly, user demand for applicationsoperating via the networks, unit cost of network capacity, and logisticsof network utilization may have substantial impacts on a preferred levelof network capacity. The challenge becomes especially severe when newlarge-scale applications are rolled out which result in additionalnetwork utilization requiring additional network capacity. For example,an addition of an enterprise resource planning system (e.g., such as anERP system R/3 sold by SAP) frequently results in a significant increaseof network utilization and thus requires an expansion of networkcapacity. Meeting such a demand for additional network capacity within aglobal enterprise network is further complicated by differing logistics,service arrangements, and lag times for provisioning network capacity ineach region or country.

Another complication of managing network capacity involves a need tobalance between delivering an acceptable response time for applicationsoperating via networks and avoiding a waste of working capital. Asnetwork capacity increases, users of networks may experience a fasterapplication response time. Nevertheless, without careful forecasting andplanning, increasing network capacity to achieve faster applicationresponse time often results in over-provisioning of network capacity,which may waste network resources and increase costs for maintainingnetworks.

Accordingly, there is a need for systems and methods that provideadvance information regarding future user demand for networks so thatappropriate planning to expand or reduce network capacity is possible.There is also a need for systems and methods that predict networkcapacity requirements so that networks may remain adequate andefficiently utilized with respect to increased or decreased networkusage. In addition, there is a need for systems and methods thatanticipate a need for improved application performance in networkswithout over-provisioning of network capacity resulting in wastedworking capital.

BRIEF SUMMARY OF THE INVENTION

In order to solve these and other needs in the art, the inventors hereofhave succeeded at designing systems and methods for maintaining acapacity of a network and anticipating demand for the network.Embodiments of the present invention effectively utilize datarepresentative of a present network capacity, present user demand, andcurrent network utilization to forecast network requirements at a futurepoint in time. Embodiments of the invention also advantageously allowprompt purchase and installation of additional network capacity in orderto accommodate increased user demand for the network. Additionally,embodiments of the invention advantageously allow evaluation of networkutilization and user demand to remove over-provisioned network capacityand to avoid wasting of working capital.

In one form, the invention is a method of maintaining capacity of anetwork. Future times are defined at which a capacity of the network isevaluated. A total capacity of the network (TNC) at each of the futuretimes is determined. A total demand of users (TUD) for the network ateach of the future times is determined. A predicted utilization (PU) ofthe network is determined at each of the future times as a function ofthe total demand of users (TUD) and the total capacity of the network(TNC). An acceptable utilization of the network at each of the futuretimes is defined. The predicted utilization (PU) of the network iscompared to the acceptable utilization of the network at each of thefuture times. In response to the comparing, for each future time, achange in network capacity (DCNC) to be applied to the network in orderto increase or decrease the capacity of the network is determined.

In another form, the invention is a system to maintain capacity of anetwork. The system includes comprises computer-executable instructionsto:

-   -   define future times at which a capacity of the network is        evaluated;    -   determine a total capacity of the network (TNC) at each of the        future times;    -   determine a total demand of users (TUD) for the network at each        of the future times;    -   determine a predicted utilization (PU) of the network at each of        the future times as a function of the total demand of users        (TUD) and the total capacity of the network (TNC);    -   define an acceptable utilization of the network at each of the        future times;    -   compare the predicted utilization (PU) of the network to the        acceptable utilization of the network at each of the future        times; and    -   determine, for each future time, a change in network capacity        (DCNC) to be applied to the network in order to increase or        decrease the capacity of the network.

In another form, the invention is a computer-readable medium havingcomputer-executable instructions to perform a method to maintaincapacity of a network. The method comprises:

-   -   defining future times at which a capacity of the network is        evaluated;    -   determining a total capacity of the network (TNC) at each of the        future times;    -   determining a total demand of users (TUD) for the network at        each of the future times;    -   determining a predicted utilization (PU) of the network at each        of the future times as a function of the total demand of users        (TUD) and the total capacity of the network (TNC);    -   defining an acceptable utilization of the network at each of the        future times;    -   comparing the predicted utilization (PU) of the network to the        acceptable utilization of the network at each of the future        times; and    -   determining in response to the comparing, for each future time,        a change in network capacity (DCNC) to be applied to the network        in order to increase or decrease the capacity of the network.

Alternatively, the invention may comprise various other methods andapparatuses.

Other features will be in part apparent and in part pointed outhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS AND TABLES

FIG. 1 is an exemplary diagram illustrating a process according to oneembodiment of the invention for anticipating demand for a network andmaintaining capacity of a network.

FIG. 2 is an exemplary diagram illustrating a process according to oneembodiment of the invention for determining a change in network capacityto be applied to a network.

FIG. 3 is an exemplary diagram illustrating a process according to oneembodiment of the invention for defining a maximum acceptableutilization and a minimum acceptable utilization of a network at afuture point in time.

FIG. 4 is a diagram of an exemplary embodiment of a system according toone embodiment of the invention adapted to anticipate demand for anetwork and to maintain capacity of a network.

TABLE 1 illustrates variations in a predicted utilization of a networkas user demand for the network changes over time without any determinedchange in network capacity.

TABLE 2 corresponds to TABLE 1 and illustrates calculating a determinedchange in network capacity to compensate a change in user demand for thenetwork.

TABLE 3 corresponds to TABLE 2 and illustrates implementation ofembodiments of the invention such that a determined change in networkcapacity is applied to a network to maintain an adjusted predictedutilization at a level between a minimum acceptable utilization and amaximum acceptable utilization.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

Definitions

Within the context of this specification, each term or phrase below willinclude, but will not be considered necessarily limited to, thefollowing meaning or meanings.

PRESENT NETWORK CAPACITY (PNC) is an objective measure of an existingnetwork capacity. For example, PRESENT NETWORK CAPACITY (PNC) may be asum of an amount of data capable of being transmitted via the networkwithin a period of time (i.e., a data transmission rate). An exemplaryPRESENT NETWORK CAPACITY (PNC) for Time 0 (T0) to Time 8 (T8) isindicated in boxes C2-K2 of TABLES 1, 2, and 3.

PLANNED CHANGE IN NETWORK CAPACITY (PCNC) is the same objective measureas PRESENT NETWORK CAPACITY (PNC) and indicates an amount of networkcapacity planned to be added to or removed from an existing network dueto anticipated or planned modifications to the network. PLANNED CHANGEIN NETWORK CAPACITY (PCNC) may be positive or negative depending onwhether the network capacity increases or decreases. An exemplaryPLANNED CHANGE IN NETWORK CAPACITY (PCNC) for T0 to T8 is indicated inboxes C3-K3 of TABLES 1, 2, and 3.

TOTAL NETWORK CAPACITY (TNC=PNC+PCNC) is a sum of PRESENT NETWORKCAPACITY (PNC) and PLANNED CHANGE IN NETWORK CAPACITY (PCNC) andindicates a total anticipated network capacity after PLANNED CHANGE INNETWORK CAPACITY (PCNC) is added to or removed from an existing networkdue to anticipated modifications. An exemplary TOTAL NETWORK CAPACITY(TNC) for T0 to T8 is indicated in boxes C4-K4 of TABLES 1, 2, and 3.

PRESENT USER DEMAND (PUD) is an amount indicative of a network capacitypresently required by users of a network. An exemplary PRESENT USERDEMAND (PUD) for T0 to T8 is indicated in boxes C5-K5 of TABLES 1, 2,and 3.

CHANGE IN USER DEMAND (CUD) is an amount indicative of an anticipatedchange in network capacity that may be needed to meet specific eventsresulting in increased or decreased user demand for a network. CHANGE INUSER DEMAND (CUD) may be positive or negative depending on whether userdemand for the network increases or decreases. An exemplary CHANGE INUSER DEMAND (CUD) for T0 to T8 is indicated in boxes C6-K6 of TABLES 1,2, and 3.

TOTAL USER DEMAND (TUD=PUD+CUD) is a sum of PRESENT USER DEMAND (PUD)and CHANGE IN USER DEMAND (CUD) and indicates an anticipated networkcapacity that may be required by users of a network at a future point intime. An exemplary TOTAL USER DEMAND (TUD) for T0 to T8 is indicated inboxes C7-K7 of TABLES 1, 2, and 3.

PREDICTED UTILIZATION (PU=TUD/TNC) is TOTAL USER DEMAND (TUD) divided byTOTAL NETWORK CAPACITY (TNC) and is a predicted percent usage of anetwork capacity at a future point in time. An exemplary PREDICTEDUTILIZATION (PU) for T0 to T8 is indicated in boxes C8-K8 of TABLES 1,2, and 3.

MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) is a preferred maximum percentusage of a network capacity. An exemplary MAXIMUM ACCEPTABLE UTILIZATION(MaxAU) for T0 to T8 is indicated in boxes C9-K9 of TABLES 1, 2, and 3.

MINIMUM ACCEPTABLE UTILIZATION (MinAU) is a preferred minimum percentusage of a network capacity. An exemplary MINIMUM ACCEPTABLE UTILIZATION(MinAU) for T0 to T8 is indicated in boxes C10-K10 of TABLES 1, 2, and3.

CURRENT UTILIZATION (CU) is a current percent usage of a networkcapacity.

DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is an amount of networkcapacity that needs to be added to or removed from a network toaccommodate an increase or decrease of user demand. DETERMINED CHANGE INNETWORK CAPACITY (DCNC) may be positive or negative depending on whetherthe network capacity increases or decreases. An exemplary DETERMINEDCHANGE IN NETWORK CAPACITY (DCNC) for T0 to T8 is indicated in boxesC11-K11 of TABLES 2 and 3.

ADJUSTED TOTAL NETWORK CAPACITY (ATNC=TNC+DCNC) is a sum of TOTALNETWORK CAPACITY (TNC) and DETERMINED CHANGE IN NETWORK CAPACITY (DCNC)and indicates an adjusted total anticipated network capacity afterDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is applied to a network. Anexemplary TOTAL NETWORK CAPACITY (TNC) for T0 to T8 is indicated inboxes C12-K12 of TABLE 3.

ADJUSTED PREDICTED UTILIZATION (APU=TUC/ATNC) is TOTAL USER DEMAND (TUD)divided by ADJUSTED TOTAL NETWORK CAPACITY (ATNC) and is an adjustedpredicted percent usage of a network capacity at a future point in timeafter DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is applied to anetwork. An exemplary ADJUSTED PREDICTED UTILIZATION (APU) for T0 to T8is indicated in boxes C13-K13 of TABLE 3.

INSTALLATION indicates an amount of time (e.g., days) needed to installDETERMINED CHANGE IN NETWORK CAPACITY (DCNC).

ADVANCE PURCHASE indicates an amount of time (e.g., days) needed frompurchase order to delivery of DETERMINED CHANGE IN NETWORK CAPACITY(DCNC).

LEAD TIME is a sum of INSTALLATION and ADVANCE PURCHASE.

These terms may be defined with additional language or by additionalexamples in the remaining portions of the specification, and alsoencompass their ordinary and customary meaning(s).

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates generally one method (indicated generally byreference character 100) according to one embodiment of the inventionfor anticipating demand for a network and maintaining capacity of anetwork, which may be implemented manually or via software. At 102,method 100 determines a PRESENT NETWORK CAPACITY (PNC) of the network.The PRESENT NETWORK CAPACITY (PNC) generally indicates a presentcapacity of the network in handling a user demand for one or moreapplications operating via the network. According to one embodiment ofthe invention, the network may have either a fixed or a burstablecapacity. A fixed capacity network maintains a substantially fixedbandwidth throughout data transmission. One example of a fixed capacitynetwork is a dedicated T-1 line, which is capable of transmitting dataat a substantially constant 1.544 megabits per second (Mbps). In thepreferred embodiment of the invention, PRESENT NETWORK CAPACITY (PNC)for a fixed capacity network is the fixed bandwidth of the network. Aburstable capacity network (e.g., Frame-Relay or asynchronous transfermode (ATM) circuit), on the other hand, allows data transmission rate toexceed a predefined network bandwidth for a period of time. Preferably,method 100 may determine PRESENT NETWORK CAPACITY (PNC) of a burstablecapacity network to be the network's predefined network bandwidth.

At 104, method 100 determines a PRESENT USER DEMAND (PUD) for thenetwork. The PRESENT USER DEMAND (PUD) generally indicates an amount ofnetwork capacity presently required by users of the network. In general,as user demand for applications operating via the network increases,demand for the network capacity also increases. In other words, PRESENTUSER DEMAND (PUD) may depend on how many users request data from anapplication operating via the network. If the application has asubstantial number of users, then the network may require more networkcapacity to transmit application data to the users.

At 106, method 100 defines one or more future times at which the networkcapacity and user demand for the network are evaluated. In the preferredembodiment of the invention, each of the future times may be defined asa function of fixed time intervals. For example, the future times may bedefined as a function of one-year intervals so that the network capacityand user demand for the network are annually evaluated. In analternative embodiment of the invention, method 100 may define thefutures times based on a particular type of network forecast desired.For example, to evaluate both shorter and longer projections of thenetwork capacity and user demand, the future times may be defined as onemonth, six month, one year, and then two years from a present time. Inaddition, it is to be understood that the future times may be defined inany other manner as desired, such as anticipated times of growth. At108, method 100 selects a first future time of the defined future timesto begin evaluating the network capacity and user demand.

At 110, method 100 determines a PLANNED CHANGE IN NETWORK CAPACITY(PCNC) that may be added to or removed from the network between thepresent time and the future time selected at 108. The PLANNED CHANGE INNETWORK CAPACITY (PCNC) generally reflects an increase or decrease ofnetwork capacity that will result from anticipated or plannedmodifications to the existing network. For example, a 5% increase ofnetwork capacity may be anticipated or planned for each of the futuretimes. Proceeding to 112, method 100 determines a TOTAL NETWORK CAPACITY(TNC) of the network at the selected future time. According to oneexemplary embodiment of the invention, method 100 derives the TOTALNETWORK CAPACITY (TNC) by adding PRESENT NETWORK CAPACITY (PNC) andPLANNED CHANGE IN NETWORK CAPACITY (PCNC).

In one embodiment of the invention, method 100 determines at 114 aCHANGE IN USER DEMAND (CUD) for the network anticipated at the selectedfuture time. The CHANGE IN USER DEMAND (CUD) generally indicates anincrease or decrease of user demand for the network that may occurbetween the present time and the selected future time. Particularly, asa number of users accessing an application operating via the networkchanges, user demand for the network changes as well. For example, userdemand for the network may increase after a new application or a newerversion of an application is rolled out to clients coupled to thenetwork. In contrast, loss of users for an application may result indecreased user demand for the network. Accordingly, CHANGE IN USERDEMAND (CUD) may indicate either a growth or shrinking of PRESENT USERDEMAND (PUD).

Proceeding to 116, method 100 determines a TOTAL USER DEMAND (TUD)anticipated at the selected future time. In one exemplary embodiment ofthe invention, the TOTAL USER DEMAND (TUD) is determined by summingPRESENT USER DEMAND (PUD) and CHANGE IN USER DEMAND (CUD). In general,TOTAL USER DEMAND (TUD) indicates an anticipated network capacityrequired by users of applications operating via the network at theselected future time.

According to one embodiment of the invention, method 100 determines at118 a PREDICTED UTILIZATION (PU) of the network at the selected futuretime. The PREDICTED UTILIZATION (PU) generally indicates how muchnetwork capacity users are likely to utilize at the selected futuretime. In one exemplary embodiment of the invention, PREDICTEDUTILIZATION (PU) indicates a percentage of network usage (i.e., percentusage) at the selected future time and is calculated as TOTAL USERDEMAND (TUD) divided by TOTAL NETWORK CAPACITY (TNC).

At 120, method 100 may define a MAXIMUM ACCEPTABLE UTILIZATION (MaxAU)of the network at the selected future time. In one embodiment of theinvention, the MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) generallyindicates a percentage representative of a preferred maximum usage ofthe network capacity (e.g., 85% of the network capacity). In anotherembodiment of the invention, method 100 may specify multiple levels ofMAXIMUM ACCEPTABLE UTILIZATION (MaxAU) to designate degrees of networkutilization preferences. For example, method 100 may specify a firstlevel of MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) at 70% of the networkcapacity and a second level of MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) at85% of the network capacity. In this particular example, a network usagebelow the first level may indicate that the network can effectivelyaccommodate user demand. A network usage above the first level but belowthe second level may indicate that the network is having difficulty inaccommodating user demand and thus a further analysis of the networkutilization is warranted. Furthermore, in this example, a network usageabove the second level may indicate that the network is over-utilizedsuch that managers of the network may need to expand the networkcapacity.

According to one embodiment of the invention, method 100 may also definea MINIMUM ACCEPTABLE UTILIZATION (MinAU), which generally indicates apercentage representative of a preferred minimum usage of the networkcapacity. For example, method 100 may define the MINIMUM ACCEPTABLEUTILIZATION (MinAU) to be 30% of the network capacity. Therefore,according to this particular example, if users utilize less than 30% ofthe network capacity, managers of the network may consider reducing thenetwork capacity to minimize costs for maintaining the network and avoidwasted working capital (e.g., by reducing idle network capacity).

Proceeding to 122, method 100 compares PREDICTED UTILIZATION (PU) at theselected future time with both MINIMUM ACCEPTABLE UTILIZATION (MinAU)and MAXIMUM ACCEPTABLE UTILIZATION (MaxAU). According to one exemplaryembodiment of the invention, if PREDICTED UTILIZATION (PU) is at a levelbetween MINIMUM ACCEPTABLE UTILIZATION (MinAU) and MAXIMUM ACCEPTABLEUTILIZATION (MaxAU), then the predicted network usage at the selectedfuture time is at a preferred level and no increase or decrease of thenetwork capacity is needed to meet anticipated changes in user demand.Accordingly, method 100 may return to 108 to select a next definedfuture time to be evaluated, until every one of the defined future timeshas been selected.

According to another exemplary embodiment of the invention, if PREDICTEDUTILIZATION (PU) is less than MINIMUM ACCEPTABLE UTILIZATION (MinAU),then the network may be over-provisioned given the level of user demandat the selected future time. In such a scenario, a reduction of thenetwork capacity may be warranted. In contrast, if PREDICTED UTILIZATION(PU) is greater than MAXIMUM ACCEPTABLE UTILIZATION (MaxAU), then thenetwork may not have adequate capacity to accommodate user demand at theselected future time. In both scenarios, method 100 may determine aDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) for the network at 124. TheDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) generally indicates anamount of network capacity that needs to be added to or removed from thenetwork in order for an ADJUSTED PREDICTED UTILIZATION (APU) of thenetwork to be at a level between MINIMUM ACCEPTABLE UTILIZATION (MinAU)and MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) at the selected future time.According to an embodiment, DETERMINED CHANGE IN NETWORK CAPACITY (DCNC)may be either positive or negative depending if network capacity needsto be added to or removed from the network.

In the scenario that DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) ispositive (i.e., network capacity needs to be added to the network),method 100 may determine at 126 a LEAD TIME for DETERMINED CHANGE INNETWORK CAPACITY (DCNC). In general, the LEAD TIME is a sum of anADVANCE PURCHASE and an INSTALLATION and indicates an amount of timeneeded for delivery and installation of purchased DETERMINED CHANGE INNETWORK CAPACITY (DCNC). For example, if the time to deliver purchasedDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is one month (i.e., ADVANCEPURCHASE) and the time to install DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) is another month (i.e., INSTALLATION), then LEAD TIME may be twomonths. According to this particular example and at 128, method 100 mayinitiate procurement of DETERMINED CHANGE IN NETWORK CAPACITY (DCNC)(e.g., by placing a purchase order) at least two months prior to theselected future time in order to have DETERMINED CHANGE IN NETWORKCAPACITY (DCNC) installed at the selected future time to accommodateuser demand for the network. The method 100 then returns to 108 toselect the next defined future time.

According to one embodiment of the invention, in the scenario thatDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is positive, method 100 mayalso plan a budget for DETERMINED CHANGE IN NETWORK CAPACITY (DCNC), asindicated at 130. In particular, method 100 may determine a projectedcost measure of DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) (e.g., inunit cost and/or total cost) in order to facilitate budged planning forfuture expansion of the network capacity. In one exemplary embodiment ofthe invention, method 100 may project a unit cost of DETERMINED CHANGEIN NETWORK CAPACITY (DCNC) (e.g., cost per kilobit) at a future time byanalyzing past trends of unit cost increases or decreases for networkswith a similar size, distance, and location (i.e., unit cost may varyaccording to network size, link distance, and region/country ofnetwork). Using the projected unit cost of DETERMINED CHANGE IN NETWORKCAPACITY (DCNC), method 100 may calculate a projected total cost ofDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) at the future time.Alternatively, method 100 may multiply a current unit cost of networkcapacity by DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) to derive theprojected total cost of DETERMINED CHANGE IN NETWORK CAPACITY (DCNC)without analyzing past trends of unit cost increases or decreases. Thisembodiment of the invention advantageously allows managers of thenetwork to examine financial viability of network capacity procurement.

In the scenario that DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) isnegative (i.e., network capacity needs to be removed from the network),method 100 may initiate removal of DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) from the network 128 so that the ADJUSTED PREDICTED UTILIZATION(APU) may be greater than or equal to MINIMUM ACCEPTABLE UTILIZATION(MinAU) before or at the selected future time, as indicated at 132. Themethod 100 then returns to 108 to select the next defined future time.

It is to be understood that the illustrated order of method 100 is forillustration purpose only. Accordingly, method 100 does not require anydefined order of steps. It is contemplated that any particular step ofmethod 100 may be performed before, contemporaneously with, or afteranother step without changing the scope of the invention. TABLE 1 T0 T1T2 T3 T4 T5 T6 T7 T8 PNC PRESENT 400 400 400 440 440 484 484 532 532NETWORK CAPACITY PCNC PLANNED 0 0 40 0 44 0 48 0 53 CHANGE IN NETWORKCAPACITY TNC = PNC + PCNC TOTAL 400 400 440 440 484 484 532 532 585NETWORK CAPACITY PUD PRESENT 340 340 320 110 90 120 420 460 500 USERDEMAND CUD CHANGE IN 0 −20 −210 −20 30 300 40 40 20 USER DEMAND TUD =PUD + CUD TOTAL USER 340 320 110 90 120 420 460 500 520 DEMAND PU = TUD/PREDICTED 85% 80% 25% 20% 25% 87% 86% 94% 89% TNC UTILIZATION MaxAUMAXIMUM 85% 85% 85% 85% 85% 80% 80% 75% 70% varies ACCEPTABLEUTILIZATION MinAU MINIMUM 30% 30% 30% 30% 30% 35% 35% 40% 45% variesACCEPTABLE UTILIZATION

TABLE 1 illustrates variations in PREDICTED UTILIZATION (PU) of thenetwork as TOTAL USER DEMAND (TUD) changes over time without anycorresponding DETERMINED CHANGE IN NETWORK CAPACITY (DCNC). As can beseen in TABLE 1, there is a positive PLANNED CHANGE IN NETWORK CAPACITY(PCNC) of 10% in T2, T4, T6, and T8. As a result, TOTAL NETWORK CAPACITY(TNC) is anticipated to increase by 10% in T2, T4, T6, and T8.Nevertheless, CHANGE IN USER DEMAND (CUD), and as a result, TOTAL USERDEMAND (TUD), for the network also varies throughout T0 to T8. Withoutany DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) added to or removedfrom the network, PREDICTED UTILIZATION (PU) at a particular future timemay fall below MINIMUM ACCEPTABLE UTILIZATION (MinAU) or rise aboveMAXIMUM ACCEPTABLE UTILIZATION (MaxAU). For example, at T2, a CHANGE INUSER DEMAND (CUD) of −210 (and thus a TOTAL USER DEMAND (TUD) of 110)causes PREDICTED UTILIZATION (PU) to fall to 25%, which is below theMINIMUM ACCEPTABLE UTILIZATION (MinAU) of 30%. In another example, atT7, a CHANGE IN USER DEMAND (CUD) of +40 (and thus a TOTAL USER DEMAND(TUD) of 500) causes PREDICTED UTILIZATION (PU) to rise to 94%, which isabove the MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) of 75%. It is notedthat MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) and MINIMUM ACCEPTABLEUTILIZATION (MinAU) vary across T0 to T8 to reflect a preferred networkutilization at a particular future point in time. TABLE 2 T0 T1 T2 T3 T4T5 T6 T7 T8 PNC PRESENT 400 400 400 440 440 484 484 532 532 NETWORKCAPACITY PCNC PLANNED 0 0 40 0 44 0 48 0 53 CHANGE IN NETWORK CAPACITYTNC = PNC + PCNC TOTAL 400 400 440 440 484 484 532 532 585 NETWORKCAPACITY PUD PRESENT 340 340 320 110 90 120 420 460 500 USER DEMAND CUDCHANGE IN 0 −20 −210 −20 30 300 40 40 20 USER DEMAND TUD = PUD + CUDTOTAL USER 340 320 110 90 120 420 460 500 520 DEMAND PU = TUD/ PREDICTED85% 80% 25% 20% 25% 87% 86% 94% 89% TNC UTILIZATION MaxAU MAXIMUM 85%85% 85% 85% 85% 80% 80% 75% 70% varies ACCEPTABLE UTILIZATION MinAUMINIMUM 30% 30% 30% 30% 30% 35% 35% 40% 45% varies ACCEPTABLEUTILIZATION DCNC DETERMINED 0 0 −73 −140 −84 41 43 135 158 CHANGE INNETWORK CAPACITY

TABLE 2 similarly illustrates variations in PREDICTED UTILIZATION (PU)of the network from T0 to T8 but now calculates corresponding DETERMINEDCHANGES IN NETWORK CAPACITY (DCNC). In TABLE 2, a DETERMINED CHANGE INNETWORK CAPACITY (DCNC) is separately calculated for each future time tocompensate a change in TOTAL USER DEMAND (TUD) at the same future time.In particular, according to an embodiment of the invention, theDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is calculated as an amountof TOTAL NETWORK CAPACITY (TNC) increase or decrease such that PREDICTEDUTILIZATION (PU) of the network at a particular future time is increasedor decreased to a level between MINIMUM ACCEPTABLE UTILIZATION (MinAU)and MAXIMUM ACCEPTABLE UTILIZATION (MaxAU). As one example, at T2, aDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) of −73 is needed tocompensate a CHANGE IN USER DEMAND (CUD) of −210. Similarly, at T7, aDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) of +135 is needed tocompensate a CHANGE IN USER DEMAND (CUD) of +40. In contrast, at T1,since PREDICTED UTILIZATION (PU) is at a level between MINIMUMACCEPTABLE UTILIZATION (MaxAU) and MINIMUM ACCEPTABLE UTILIZATION(MinAU), no DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) needs to beadded to or removed from the network to accommodate increased ordecreased user demand. It is noted that in TABLE 2, even though aDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is calculated for eachfuture time, the DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) is notadded to or removed from the network. Accordingly, in TABLE 2, thePRESENT NETWORK CAPACITY (PNC) at each future time does not take intoaccount the DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) of the previousfuture time. TABLE 3 T0 T1 T2 T3 T4 T5 T6 T7 T8 PNC PRESENT 400 400 400367 300 344 525 573 667 NETWORK CAPACITY PCNC PLANNED 0 0 40 0 44 0 48 053 CHANGE IN NETWORK CAPACITY TNC = PNC + PCNC TOTAL 400 400 440 367 344344 573 573 720 NETWORK CAPACITY PUD PRESENT 340 340 320 110 90 120 420460 500 USER DEMAND CUD CHANGE IN 0 −20 −210 −20 30 300 40 40 20 USERDEMAND TUD = PUD + CUD TOTAL USER 340 320 110 90 120 420 460 500 520DEMAND PU = TUD/ PREDICTED 85% 80% 25% 25% 35% 122% 80% 87% 72% TNCUTILIZATION MaxAU MAXIMUM 85% 85% 85% 85% 85% 80% 80% 75% 70% variesACCEPTABLE UTILIZATION MinAU MINIMUM 30% 30% 30% 30% 30% 35% 35% 40% 45%varies ACCEPTABLE UTILIZATION DCNC DETERMINED 0 0 −73 −67 0 181 0 94 23CHANGE IN NETWORK CAPACITY ATNC = TNC + DCNC ADJUSTED 400 400 367 300344 525 573 667 743 TOTAL NETWORK CAPACITY APU = TUD/ ADJUSTED 85% 80%30% 30% 35% 80% 80% 75% 70% ATNC PREDICTED UTILIZATION

TABLE 3 corresponds to TABLE 2 and illustrates implementation ofembodiments of the invention. Specifically, a DETERMINED CHANGE INNETWORK CAPACITY (DCNC) will be applied to the network at each futuretime to maintain an ADJUSTED PREDICTED UTILIZATION (APU) of the networkat a level between MINIMUM ACCEPTABLE UTILIZATION (MinAU) and MAXIMUMACCEPTABLE UTILIZATION (MaxAU). For example, at T2, a DETERMINED CHANGEIN NETWORK CAPACITY (DCNC) of −73 is needed to compensate a CHANGE INUSER DEMAND (CUD) of −210. After removing the DETERMINED CHANGE INNETWORK CAPACITY (DCNC) from the network at T2, TOTAL NETWORK CAPACITY(TNC) is adjusted to become an ADJUSTED TOTAL NETWORK CAPACITY (ATNC) of367 (i.e., 440-73). As such, PREDICTED UTILIZATION (PU) of the networkis adjusted to become an ADJUSTED PREDICTED UTILIZATION (APU) of 30%(i.e., 110/367) at T2, which is at a level between MINIMUM ACCEPTABLEUTILIZATION (MinAU) and MAXIMUM ACCEPTABLE UTILIZATION (MaxAU).

Also can be seen in TABLE 3, after a DETERMINED CHANGE IN NETWORKCAPACITY (DCNC) is applied to the network at a particular future time,PRESENT NETWORK CAPACITY (PNC) of the next future time reflects theapplied DETERMINED CHANGE IN NETWORK CAPACITY (DCNC). For example,ADJUSTED TOTAL NETWORK CAPACITY (ATNC) of T2 is carried over to bePRESENT NETWORK CAPACITY (PNC) of T3; ADJUSTED TOTAL NETWORK CAPACITY(ATNC) of T3 is carried over to be PRESENT NETWORK CAPACITY (PNC) of T4;and so on. Therefore, according to the embodiment of the inventionillustrated in TABLE 3, the network capacity changes as PLANNED CHANGEIN NETWORK CAPACITY (PCNC) and DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) are applied to the network. As such, determining a PREDICTEDUTILIZATION (PU) at a particular future time includes taking intoaccount both the PLANNED CHANGE IN NETWORK CAPACITY (PCNC) andDETERMINED CHANGE IN NETWORK CAPACITY (DCNC).

FIG. 2 illustrates generally a method 200 according to one embodiment ofthe invention for determining a DETERMINED CHANGE IN NETWORK CAPACITY(DCNC). According to an exemplary embodiment of the invention, at 202,the method 200 may consider various factors in determining theDETERMINED CHANGE IN NETWORK CAPACITY (DCNC), including: a CURRENTUTILIZATION (CU) of the network at 204, a network utilization growthtrend at 206, and a cost measure of capacity to be added to the networkat 208. In general, the CURRENT UTILIZATION (CU) of the network is anindication of how users are currently utilizing the network. In oneembodiment of the invention, method 200 may collect data samples over aperiod of time indicating how much network capacity users of the networkare utilizing.

According to the preferred embodiment of the invention, method 200 mayevaluate CURRENT UTILIZATION (CU) of the network based on percentiles ofnetwork usage. In one form, a percentile of network usage indicates ahighest percent usage of the network capacity for a particularpercentage of time. For example, a 75% network usage at 95th percentileindicates that for 95% of the time, users are utilizing less than 75% ofthe network capacity.

The method 200 may use percentile-based CURRENT UTILIZATION (CU) todetermine DETERMINED CHANGE IN NETWORK CAPACITY (DCNC) at 202. IfCURRENT UTILIZATION (CU) of the network across a range of percentilessubstantially remains within a level between MINIMUM ACCEPTABLEUTILIZATION (MinAU) and MAXIMUM ACCEPTABLE UTILIZATION (MaxAU), thenmethod 200 may determine that there is no DETERMINED CHANGE IN NETWORKCAPACITY (DCNC). This may be the case even if at a higher percentile(e.g., 99th percentile) or at a lower percentile (e.g., 30thpercentile), CURRENT UTILIZATION (CU) rises above MAXIMUM ACCEPTABLEUTILIZATION (MaxAU) or falls below MINIMUM ACCEPTABLE UTILIZATION(MinAU), respectively. Such infrequent over-utilization orunder-utilization of the network may not warrant an increase or decreasein the network capacity, since the network may accommodate user demandfor a majority of time.

In contrast, if CURRENT UTILIZATION (CU) of the network remains aboveMAXIMUM ACCEPTABLE UTILIZATION (MaxAU) of below MINIMUM ACCEPTABLEUTILIZATION (MinAU) across a range of percentiles (e.g., from 30thpercentile to 99th percentile), method 200 may determine a positive ornegative DETERMINED CHANGE IN NETWORK CAPACITY (DCNC). Such frequentover-utilization or under-utilization of the network generally indicatesthat the network capacity needs to be increased or decreased in order toaccommodate increased user demand or to avoid wasted network resources.

According to one embodiment of the invention, the network utilizationgrowth trend as indicated at 206 is another factor in determiningDETERMINED CHANGE IN NETWORK CAPACITY (DCNC). Based on the determinedCURRENT UTILIZATION (CU) of the network and/or past growth of thenetwork utilization, method 200 may project a growth trend of thenetwork utilization. In one exemplary embodiment of the invention,method 200 may plot data samples representative of past utilizations ofthe network against time. By determining a regression of the plotteddata samples, method 200 may estimate a future utilization of thenetwork at a plurality of future points in time and thus may determinean estimated network utilization growth trend. If the estimated networkutilization growth trend projects a higher network utilization at aparticular future point in time, then a positive DETERMINED CHANGE INNETWORK CAPACITY (DCNC) may be needed to meet an increased user demandfor the network. If the estimated network growth trend projects a lowernetwork utilization at a particular future point in time, then method200 may determine a negative DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) so that the network capacity at the particular future point intime is reduced to avoid wasted working capital.

The cost measure of capacity to be added to the network, as indicated at208, may be another factor in determining DETERMINED CHANGE IN NETWORKCAPACITY (DCNC). For example, if the unit cost of network capacity andthe resulting total cost are greater than a planned budget for addingcapacity to the network, then method 200 may determine that the benefitof additional capacity is outweighed by the excess costs. On the otherhand, if the unit cost of network capacity and the resulting total costare within the planned budget, method 200 may determine a positiveDETERMINED CHANGE IN NETWORK CAPACITY (DCNC), even if the network mayaccommodate current and projected user demand without additional networkcapacity. Purchasing or keeping inexpensive network capacity mayadvantageously allow network managers to sustain unanticipated futureuser demand for the network without incurring substantial costs.

FIG. 3 illustrates generally a method 300 according to one embodiment ofthe invention for defining a MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) anda MINIMUM ACCEPTABLE UTILIZATION (MinAU) of the network. According toone exemplary embodiment of the invention, the method 300 definesMAXIMUM ACCEPTABLE UTILIZATION (MaxAU) and MINIMUM ACCEPTABLEUTILIZATION (MinAU) of the network at 302 as a function of a responsetime of an application operating via the network, as indicated at 304.In general, response time of an application is directly impacted by thetime needed to transmit data over the network. Thus, it is desirable tominimize response time in order to enhance the user's experience of theapplication. According to the preferred embodiment of the invention,method 300 may define MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) such thatthe network would not be over-utilized to affect substantially aresponse time of an application operating via the network. Preferably,method 300 may also define a target response time so that MAXIMUMACCEPTABLE UTILIZATION (MaxAU) is defined as the highest networkutilization that would result in the target response time. In addition,method 300 may define MINIMUM ACCEPTABLE UTILIZATION (MinAU) at a levelwhere no substantial reduction in response time would result fromfurther reduction of network utilization.

In one exemplary embodiment of the invention, a response time of anapplication operating via the network may be based on a number offactors. As indicated at 306, the response time may depend on a distancebetween a client and a server of the application operating via thenetwork. Generally, the distance between the client and the server isproportional to the response time of the application (e.g., the longerthe distance, the longer the response time). Thus, method 300 mayconsider a weighted distance between the server and each client todetermine an approximate response time of the application.

At 308, method 300 may also consider a connection speed of a clientcoupled to the network in determining the response time of theapplication. Clients with faster network connections are able to receiveapplication data faster than clients with slower network connections.For example, clients coupled to the network via broadband (e.g., DigitalSubscriber Line (DSL), cable modem, etc.) operating at a speed of 128Kbps or higher may experience faster response times than clients coupledto the network via dial-up modem, which operates at a speed of 56 Kbpsor lower. Accordingly, the network may be able to maintain a fasterresponse time if clients of the application are coupled to the networkvia a faster network connection.

Network utilization during a period of time at which a client accessesthe application may also affect the response time of the application, asindicated at 310. For example, during busy hours of network traffic(e.g., during working hours), a network serialization delay may resultfrom higher network utilization and queuing of user demands. Such anetwork serialization delay may increase the response time of theapplication. According to one embodiment of the invention, method 300may evaluate a frequency of network serialization delay (e.g., by usingpercentile-based network utilization data) to determine the applicationresponse time at particular time intervals (e.g., 12 pm to 5 pm, 5 pm to10 pm, 10 pm to 12 am, etc.). In this embodiment of the invention,method 300 may define MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) at a levelsuch that infrequent long response time is tolerable but frequent longresponse time is intolerable.

FIG. 4 illustrates generally a system 400 according to one exemplaryembodiment of the invention adapted to anticipate demand for a networkand to maintain capacity of a network. The system 400 includes aprocessor 402, which may be any type of general purpose or specialpurpose computing systems, environments, or configurations. Examples ofwell known computing systems, environments, and configurations that maybe suitable for the processor 402 include, without limitation, personalcomputers, server computers, hand-held or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network personal computers, minicomputers,mainframe computers, distributed computing environments that include anyof the above systems or devices, and the like.

As illustrated in FIG. 4, processor 402 includes computer-executableinstructions to receive a number of inputs. At 404, processor 402 mayinclude instructions to receive one or more future times at which thenetwork capacity, network utilization, and user demand are evaluated.Processor 402 may also include instructions to receive a PRESENT NETWORKCAPACITY (PNC) at 406, a PRESENT USER DEMAND (PUD) at 408, a PLANNEDCHANGE IN NETWORK CAPACITY (PCNC) at 410, and a CHANGE IN USER DEMAND(CUD) at 412. A MAXIMUM ACCEPTABLE UTILIZATION (MaxAU) and a MINIMUMACCEPTABLE UTILIZATION (MinAU) may also be inputted to processor 402, asindicated by 414 and 416, respectively.

Based on the received inputs, processor 402 may executecomputer-executable instructions to anticipate demand for the networkand maintain capacity of the network. In particular, processor 402 mayinclude instructions to calculate a TOTAL NETWORK CAPACITY (TNC) at aparticular future time based on the PRESENT NETWORK CAPACITY (PNC) andthe PLANNED CHANGE IN NETWORK CAPACITY (PCNC), as indicated at 418.Processor 402 may also include instructions to calculate a TOTAL USERDEMAND (TUD) at the future time based on the PRESENT USER DEMAND (PUD)and the CHANGE IN USER DEMAND (CUD), as indicated at 420. At 422,processor 402 may include instructions to calculate a PREDICTEDUTILIZATION (PU) of the network at the future time by dividing the TOTALUSER DEMAND (TUD) by the TOTAL NETWORK CAPACITY (TNC), according to oneexemplary embodiment of the invention. As indicated at 424, if thePREDICTED UTILIZATION (PU) is less than the MINIMUM ACCEPTABLEUTILIZATION (MinAU) or greater than the MAXIMUM ACCEPTABLE UTILIZATION(MaxAU), then processor 402 may include instructions to calculate aDETERMINED CHANGE IN NETWORK CAPACITY (DCNC) to be applied to thenetwork. In the scenario that the DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) is positive, processor 402 may include instructions to determinea LEAD TIME at 426 such that DETERMINED CHANGE IN NETWORK CAPACITY(DCNC) may be installed to the network before or at the future time inorder to accommodate user demand.

When introducing elements of the present invention or the embodiment(s)thereof, the articles “a,” “an,” “the,” and “said” are intended to meanthat there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions, products,and methods without departing from the scope of the invention, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

1. A method of maintaining capacity of a network comprising: definingfuture times at which a capacity of the network is evaluated;determining a total capacity of the network (TNC) at each of the futuretimes; determining a total demand of users (TUD) for the network at eachof the future times; determining a predicted utilization (PU) of thenetwork at each of the future times as a function of the total demand ofusers (TUD) and the total capacity of the network (TNC); defining anacceptable utilization of the network at each of the future times;comparing the predicted utilization (PU) of the network to theacceptable utilization of the network at each of the future times; anddetermining in response to the comparing, for each future time, a changein network capacity (DCNC) to be applied to the network in order toincrease or decrease the capacity of the network.
 2. The method of claim1 wherein the acceptable utilization comprises a maximum acceptableutilization (MaxAU) of the network and a minimum acceptable utilization(MinAU) of the network.
 3. The method of claim 1 further comprisingapplying the determined change in network capacity (DCNC) to thenetwork.
 4. The method of claim 1 further comprising: determining ateach of the future times a lead time for adding product for applying thedetermined change in network capacity (DCNC) to the network; and inadvance of each future time based on the lead time determined withrespect to each particular future time, initiating efforts to obtainproduct for applying the determined change in network capacity (DCNC).5. The method of claim 4 wherein the lead time is a function of aninstallation time for installing said product and an advance purchasetime for obtaining said product.
 6. The method of claim 1 whereindetermining a total capacity of the network (TNC) at each of the futuretimes is a function of determining a present capacity of the network(PNC) and identifying a planned change in network capacity (PCNC) to beapplied the network between a present time and each of the future times.7. The method of claim 1 wherein determining a change in networkcapacity (DCNC) is a function of one or more of the following: a currentutilization (CU) of the network, a growth trend of a utilization of thenetwork, or a cost measure of a capacity to be added to the network. 8.The method of claim 7 wherein said current utilization (CU) of thenetwork is indicative of a high percent usage of a present capacity ofthe network (PNC) for a particular percentage of time.
 9. The method ofclaim 7 wherein the growth trend is based on a regression of datarepresentative of a past growth of the utilization of the network. 10.The method of claim 1 wherein determining a total demand of users (TUD)for the network at each of the future times is a function of determininga present demand of users (PUD) for the network and determining a changein demand of users (CUD) for the network between a present time and eachof the future times.
 11. The method of claim 10 wherein determining ananticipated change in demand of users (CUD) for the network comprisesdetermining a demand requirement for a roll-out of an applicationoperating via the network.
 12. The method of claim 1 wherein determininga predicted utilization (PU) of the network at each of the future timescomprises dividing the total demand of users (TUD) for the network bythe total capacity of the network (TNC) at each of the future times. 13.The method of claim 1 wherein the acceptable utilization of the networkis a function of a response time of an application operating via thenetwork.
 14. The method of claim 13 wherein the response time of theapplication is a function of one or more of the following: a distancebetween a client and a server of the application wherein said client andserver are coupled to the network, a connection speed of the client tothe network, or a utilization of the network during a period of time atwhich the client accesses the application.
 15. The method of claim 1further comprising planning a budget for applying the determined changein network capacity (DCNC) to the network and determining a cost measureof the determined change in network capacity (DCNC).
 16. One or morecomputer-readable media having computer-executable instructions forperforming the method of claim
 1. 17. A system to maintain capacity of anetwork comprising computer-executable instructions to: define futuretimes at which a capacity of the network is evaluated; determine a totalcapacity of the network (TNC) at each of the future times; determine atotal demand of users (TUD) for the network at each of the future times;determine a predicted utilization (PU) of the network at each of thefuture times as a function of the total demand of users (TUD) and thetotal capacity of the network (TNC); define an acceptable utilization ofthe network at each of the future times; compare the predictedutilization (PU) of the network to the acceptable utilization of thenetwork at each of the future times; and determine, for each futuretime, a change in network capacity (DCNC) to be applied to the networkin order to increase or decrease the capacity of the network.
 18. Thesystem of claim 17 wherein the acceptable utilization comprises amaximum acceptable utilization (MaxAU) of the network and a minimumacceptable utilization (MinAU) of the network.
 19. The system of claim17 further comprising computer-executable instructions to apply thedetermined change in network capacity (DCNC) to the network.
 20. Thesystem of claim 17 further comprising computer-executable instructionsto: determine at each of the future times a lead time for adding productfor applying the determined change in network capacity (DCNC) to thenetwork; and in advance of each future time based on the lead timedetermined with respect to each particular future time, initiate effortsto obtain product for applying the determined change in network capacity(DCNC).
 21. The system of claim 20 wherein the lead time is a functionof an installation time for installing said product and an advancepurchase time for obtaining said product.
 22. The system of claim 17wherein said computer-executable instructions to determine a totalcapacity of the network (TNC) at each of the future times comprisescomputer-executable instructions to determine a present capacity of thenetwork (PNC) and to identify a planned change in network capacity(PCNC) to be applied to the network between a present time and each ofthe future times.
 23. The system of claim 17 wherein saidcomputer-executable instructions to determine a change in networkcapacity (DCNC) comprises computer-executable instructions to determineone or more of the following: a current utilization (CU) of the network,a growth trend of a utilization of the network, or a cost measure of acapacity to be added to the network.
 24. The system of claim 23 whereinsaid current utilization (CU) of the network is indicative of a highpercent usage of a present capacity of the network (PNC) for aparticular percentage of time.
 25. The system of claim 23 wherein thegrowth trend is based on a regression of data representative of a pastgrowth of the utilization of the network.
 26. The system of claim 17wherein said computer-executable instructions to determine a totaldemand of users (TUD) for the network at each of the future timescomprises computer-executable instructions to determine a present demandof users (PUD) for the network and to determine an anticipated change indemand of users (CUD) for the network between a present time and each ofthe future times.
 27. The system of claim 26 wherein saidcomputer-executable instructions to determine an anticipated change indemand of users (CUD) for the network comprises computer-executableinstructions to determine a demand requirement for a roll-out of anapplication operating via the network.
 28. The system of claim 17wherein said computer-executable instructions to determine a predictedutilization (PU) of the network at each of the future times comprisescomputer-executable instructions to divide the total demand of users(TUD) for the network by the total capacity of the network (TNC) at eachof the future times.
 29. The system of claim 17 wherein the acceptableutilization of the network is a function of a response time of anapplication operating via the network.
 30. The system of claim 29wherein the response time of the application is a function of one ormore of the following: a distance between a client and a server of theapplication wherein said client and server are coupled to the network, aconnection speed of the client to the network, or a utilization of thenetwork during a period of time at which the client accesses theapplication.
 31. The system of claim 30 further comprisingcomputer-executable instructions to plan a budget for applying thedetermined change in network capacity (DCNC) to the network and todetermine a cost measure of the determined change in network capacity(DCNC).
 32. A computer-readable medium having computer-executableinstructions to perform a method to maintain capacity of a network, themethod comprising: defining future times at which a capacity of thenetwork is evaluated; determining a total capacity of the network (TNC)at each of the future times; determining a total demand of users (TUD)for the network at each of the future times; determining a predictedutilization (PU) of the network at each of the future times as afunction of the total demand of users (TUD) and the total capacity ofthe network (TNC); defining an acceptable utilization of the network ateach of the future times; comparing the predicted utilization (PU) ofthe network to the acceptable utilization of the network at each of thefuture times; and determining in response to the comparing, for eachfuture time, a change in network capacity (DCNC) to be applied to thenetwork in order to increase or decrease the capacity of the network.33. The computer-readable medium of claim 32 wherein the acceptableutilization comprises a maximum acceptable utilization (MaxAU) of thenetwork and a minimum acceptable utilization (MinAU) of the network. 34.The computer-readable medium of claim 32 wherein the method furthercomprises: determining at each of the future times a lead time foradding product for applying the determined change in network capacity(DCNC) to the network; and in advance of each future time based on thelead time determined with respect to each particular future time,initiating efforts to obtain product for applying the determined changein network capacity (DCNC).
 35. The computer-readable medium of claim 34wherein the lead time is a function of an installation time forinstalling said product and an advance purchase time for obtaining saidproduct.
 36. The computer-readable medium of claim 32 whereindetermining a total capacity of the network (TNC) at each of the futuretimes is a function of determining a present capacity of the network(PNC) and identifying a planned change in network capacity (PCNC) to beapplied the network between a present time and each of the future times.37. The computer-readable medium of claim 32 wherein determining achange in network capacity (DCNC) is a function of one or more of thefollowing: a current utilization (CU) of the network, a growth trend ofa utilization of the network, or a cost measure of a capacity to beadded to the network.
 38. The computer-readable medium of claim 32wherein determining a total demand of users (TUD) for the network ateach of the future times is a function of determining a present demandof users (PUD) for the network and determining a change in demand ofusers (CUD) for the network between a present time and each of thefuture times.
 39. The computer-readable medium of claim 32 whereindetermining a predicted utilization (PU) of the network at each of thefuture times comprises dividing the total demand of users (TUD) for thenetwork by the total capacity of the network (TNC) at each of the futuretimes.
 40. The computer-readable medium of claim 32 wherein theacceptable utilization of the network is a function of a response timeof an application operating via the network.
 41. The computer-readablemedium of claim 32 wherein the method further comprises planning abudget for applying the determined change in network capacity (DCNC) tothe network and determining a cost measure of the determined change innetwork capacity (DCNC).